The treatment of textiles and/or fibers with various substances in order to change the properties thereof is well known. For example, it is known that textiles may be waterproofed by coating them with natural or synthetic rubber. Substances have been developed which when sprayed onto fabrics introduce the property of stain resistance. In addition, it is known that fragrance delivery systems can be incorporated into fabrics. One such fragrance delivery system uses breakable fragrance filled microcapsules which are attached to the surface of a fabric or fiber and upon the introduction of an external force, the microcapsules break releasing the fragrance over an extended time period.
Fabrics have been given enhanced thermal properties by coating the fibers and the interstitial spaces between fibers with phase change materials and with plastic crystals (see Fabrics given enhanced thermal properties, Oct. 20, 1986; Chemical and Engineering News, Pages 15 and 16). The thermal properties of fabric are enhanced as it is impregnated with these microcapsules. More specifically, materials such as water, undergo phase changes from solid to liquid to gas at well known temperatures. Similarly, other materials such as paraffin wax undergo phase change from a solid to a liquid (fusion). At the phase change temperature, a characteristic of the material during the heating cycle is to absorb and hold a large quantity of thermal energy at a constant temperature before changing to the next phase. Thus, the material can be used as an absorber to protect an object from additional heat as a quantity of thermal energy will be absorbed by the phase change material before its temperature can rise. The phase change material may also be preheated and used as a barrier to cold, as a larger quantity of heat must be removed from the phase change material before its temperature can begin to drop.
However, the aforementioned surface mounted phase change materials are not without their deficiencies. For example, it was found that while somewhat effective, the phase change material was not durably bound to the fibers and laundering removed most of the material. Thus, the fabric lacked repeatability of thermal response as each laundering removed a portion of the phase change material, thus causing the fabric to exhibit a corresponding change in thermal properties which limited its usefulness. As a result, further work was undertaken to perfect a series of process steps for binding the phase change material to the fabric in order to extend the useful life of the enhanced thermal properties. Furthermore, as far as is known to the inventors, the usefulness of these fibers and fabrics has been applied to a broader temperature range which limits the thermal absorption or release at a specific temperature range.
It is, therefore, an object of the present invention to provide a fiber with enhanced thermal retention properties.
It is another object of the present invention to provide a fiber which will maintain its enhanced thermal properties over an extended period of time.
It is a further object of the invention to provide a fiber having enhanced thermal properties which can be produced with a minimum of process steps.
It is a still further object of the invention to provide a fiber having enhanced thermal properties which can be woven into a fabric from which articles of clothing and the like can be manufactured.
It is a still further object of the present invention to provide a fiber which displays enhanced thermal properties over a specified temperature range.